WMATA has completed a review of the ATU's concern and found that the inspection procedures currently in place are "appropriate and consistent with manufacturer guidelines," agency officials said in a press release.

As a result, mechanical inspections of 7000-series rail cars continued yesterday afternoon following additional safety briefings with employees.

"Part of creating a safety culture means taking immediate action to address concerns raised by employees," said WMATA Chief Safety Officer Patrick Lavin. "If a concern cannot be immediately resolved or requires further investigation, sometimes additional steps — such as a safety stand-down — must be taken in an abundance of caution."

The agency's decision to suspend inspections of the 7000-series cars resulted in an 18 percent decrease in available trainsets yesterday morning.